Jini na baya (PCA) wani jigon jini ne wanda ya samo asali daga jijiyar basilar kuma yana ba da jini zuwa sashin kwakwalwa na baya, gami da lobe na occipital, thalamus, tsakiyar kwakwalwa, da sassan lobe na wucin gadi. “Baya” na nufin bangaren baya ko na baya, “kwakwalwa” na nufin kwakwalwa, “jijiya” kuma tana nufin magudanar jini mai dauke da jini mai iskar oxygen daga zuciya zuwa gabobin jiki da kyallen jikin mutum. Don haka, jijiya na baya shine babban jigon jini a cikin kwakwalwa wanda ke ba da jinin oxygenated zuwa sashin baya na kwakwalwa.